Moss- Building Caterpillar. 199 



and preparing to assume the pupa state, exercises any reflec- 

 tive faculties, or is aware of what is about to occur relative 

 to its own self, we cannot admit. It enters upon a work of 

 which it has had no previous experience, and which is per- 

 formed, as far as contingencies allow, in the same manner 

 by every caterpillar of the same species. Its labours, its 

 mode of carrying them on, and the very time in which they 

 are to be commenced, are all pre-appointed ; and an in- 

 stinctive impulse urges and guides ; and with this instinct 

 its< organic endowments are in precise harmony ; nor does 

 instinct ever impel to labours for which an animal is not 

 provided. " The same wisdom," says Bonnet, " which has 

 constructed and arranged with so much art the various 

 organs of animals, and has made them concur towards one 

 determined end, has also provided that the different opera- 

 tions which are the natural results of the economy of the 

 animal should concur towards the same end. The creature 

 is directed towards his object by an invisible hand ; he exe- 

 cutes with precision, and by one effort, those works which 

 we so much admire ; he appears to act as if he reasoned, to 

 return to his labour at the proper time, to change his scheme 

 in case of need. But in all this he only obeys the secret 

 influence which drives him on. He is but an instrument 

 which cannot judge of each action, but is wound up by that 

 adorable Intelligence, which has traced out for every insect 

 its proper labours, as he has traced the orbit of each planet. 

 \Yhen, therefore, I see an insect working at the construction 

 of a nest, or a cocoon, I am impressed with respect, because 

 it seems to me that I am at a spectacle where the Supreme 

 Artist is hid behind the curtain."* 



There is a small sort of caterpillar which may be found 

 on old walls, feeding upon minute mosses and lichens, the 

 proceedings of which are well worthy of attention. They 

 are similar, in appearance and size, to the caterpillar of the 

 small cabbage-butterfly (Pontia ropce), and are smooth and 

 bluish. The material which they use in building their 

 cocoons is composed of the leaves and branchlets of green 

 * Contemplation de la Nature, part xv. chap. 38. 



